1. Technical Field
This disclosure is related to a ball grid array package for a semiconductor device and a method for its manufacture, and in particular, to such a device including structures for thermal enhancement.
2. Description of the Related Art
As semiconductor packaging has evolved to accommodate the increasing complexity and miniaturization of semiconductor devices, a number of packaging structures have been developed to meet various requirements. One of these structures is the Plastic Ball Grid Array (PBGA), in which a plastic laminate substrate is formed with appropriate electrical traces and contact pads, and a semiconductor die is mounted on the substrate, with wire bonds connecting the die to the electrical traces. The die and wire bonds are overmolded, i.e., encapsulated by molding compound in an injection molding process, and a ball grid array is formed on the opposite side of the die for attachment to a PCB. Sometimes a cavity is formed in the top surface of the substrate, into which the die is positioned. For this reason, PBGA packages are generally defined as cavity-up packages.
A Thermally Enhanced PBGE (TEPBGA), also referred to as a Heatsink PBGA (HSPBGA), includes a heatsink positioned over the die. FIG. 1 shows a TEPBGA package 100 according to known art. The package 100 includes a laminate substrate 102 on which a semiconductor die 104 is mounted, and wire bonded (at 112) to the substrate. A heatsink 106 is positioned over the die 104 and attached by an appropriate adhesive. Registration bumps 116 on the heatsink 106 mate with registration cavities 118 on the substrate 102 to guide placement of the heatsink. The heatsink and die are overmolded, with slots 114 provided in the heatsink 106 to permit the molding compound 108 to pass into the interior of the heatsink and immobilize the wire bonds 112.
Another known variation is referred to as an Enhanced PBGA (EPBGA), in which an aperture is formed in the substrate, and the laminate is mounted on one side to a heatsink. The die is mounted to the heatsink inside the aperture and wire bonded to the substrate. The die and wire bonding are overmolded, and the ball grid array is formed on the side of the substrate opposite the heatsink.
Additional information relating to the devices described above, as well as other types of PBGA packages can be found in the National Semiconductor Application Note 1126, of August 2003, the entirety of which is incorporated herein by reference.